The conical roller bearing known in the art comprise two box type sealing structures arranged on the two axial sides. Each box type sealing structure is annular as a whole and is used to seal the oil medium (usually lubricating oil) in the bearing and prevent external foreign matters from entering the bearing.
FIG. 1 is a partial cutaway view of the box type sealing structure known in the art and shows a half of the axial cross-sectional structure of the box type sealing structure. The box type sealing structure (10) known in the art comprises an oil-throwing ring (101) used to fix to the inner ring of the bearing and a sealing ring used to fix to the outer ring of the bearing, the sealing ring comprises a frame (102) fixed to the outer ring and a sealing portion (103) attached to the frame (102), and the sealing portion (103) has a plurality of sealing lips (including a primary sealing lip (105) and a plurality of secondary sealing lips (106)) extending towards the oil-throwing ring (101).
As shown in FIG. 1, a bent portion (104) is provided on the axial inner side of the oil-throwing ring axial portion (101a) extending in the axial direction (A) of the oil-throwing ring (101), the bent portion (104) extends outwards in the radial direction (R), only a small clearance exists between the bent portion (104) and the sealing portion (103) in the axial direction (A), the size of the clearance in the axial direction (A) is constant, and thus it is difficult for the oil medium on the axial inner side of the box type sealing structure (10) to enter the box type sealing structure (10).
However, the inventor finds that the oil medium will inevitably go from the above-mentioned clearance into the box type sealing structure (10) in practical applications. Once the oil medium enters the box type sealing structure (10), the oil medium in the box type sealing structure (10) can only flow towards the axial outer side, but will not return to the inside of the bearing. In this way, the oil medium will inevitably leak out of the box type sealing structure (10). Thus, the box type sealing structure (10) of the prior art cannot satisfactorily seal the oil medium.